129. Lower Prepulse Inhibition in Clinical High-Risk Group but not in Familial Risk Group for Psychosis Compared to Healthy Controls

Background: Although lower level of prepulse inhibition (PPI) of startle response is well known in schizophrenia, it is not clear when this begins. The aim of this study is to investigate acoustic PPI in clinical and familial risk of psychosis Methods: We studied PPI in a sample of individuals with Ultra High Risk (UHR) for psychosis, a group of familial risk for psychosis and healthy controls (HC). UHR was defined based on CAARMS (n = 25), FR group consist of siblings of patients with schizophrenia (n = 24). We collected clinical data by using BPRS-E, SANS, SAPS, PAS when individuals with UHR were antipsychotic-naive. A cognitive battery containing RVLT, WCST, Stroop, digit-symbol and TMT was applied to all participants. Interval between S1 (20 ms, 86 dB) and S2 (40 ms, 115 dB) was 120 ms, and there was a 70-dB background white noise during the experiment. Results: There was a significant difference in PPI among the 3 groups. Post hoc analysis showed that PPI was lower in UHR group than both FR (z = 2.27, P = .02) and HC groups (z = 2.53, P = .01), and there was no difference between FR and HC groups. Mean S1 was higher in FR group than UHR group (z = 2.23, P = .02). PPI and S1 amplitude were not found correlated with BPRS-E, SANS, SAPS scores, and cognitive test scores. Conclusion: Our findings show that PPI deficits begins before the onset of psychosis, and it is more prominent in those with clinical risk rather than familial risk for psychosis